package com.lizi.core.RPC.simple;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.net.ServerSocket;
import java.net.Socket;

public class RpcFramework {

	/**
	 * 暴露服务
	 * 
	 * @param service
	 *            服务实现
	 * @param port
	 *            端口
	 * @throws IOException
	 */
	public static void export(final Object service, int port) throws Exception {
		if (service == null) {
			throw new IllegalArgumentException(" service instance  == null ");
		}

		if (port <= 0 || port > 65535) {
			throw new IllegalArgumentException(" Invalid port " + port);
		}
		System.out.println(" Export service " + service.getClass().getName() + " on port " + port);

		ServerSocket server = new ServerSocket(port);
		
		while (true) {
			final Socket socket = server.accept();
			new Thread(new Runnable() {

				public void run() {

					// readUTF读取的必须是writeUTF写下的字符串。不同于标准UTF8编码，是java专用的字符序列格式，
					// 格式：2个字节的记录长度n字节数 跟着 n长度的utf8字节。
					// 用法也简单
					// os.writeInt(3);
					// os.writeUTF("hello world");//记住输出流输出的位置，在上面整数3后面
					// ....
					// int i=is.readInt(3); //先读整数
					// String t=is.readUTF();//在相应位置读取 ，位置和写的顺序一致
					try {
						ObjectInputStream input = new ObjectInputStream(socket.getInputStream());
						String methodName = input.readUTF();
						Class<?>[] parameterTypes = (Class<?>[]) input.readObject();
						Object[] arguments = (Object[]) input.readObject();

						ObjectOutputStream output = new ObjectOutputStream(socket.getOutputStream());
						try {
							Method method = service.getClass().getMethod(methodName, parameterTypes);
							Object result = method.invoke(service, arguments);
							output.writeObject(result);
						} catch (Throwable e) {
							output.writeObject(e);
						} finally {
							output.close();
							input.close();
						}
					} catch (ClassNotFoundException e) {
						e.printStackTrace();
					} catch (IOException e) {
						e.printStackTrace();
					}

				}
			}).start();
		}
	}

	/**
	 * 引用服务
	 * 
	 * @param <T>
	 *            接口泛型
	 * @param interfaceClass
	 *            接口类型
	 * @param host
	 *            服务器主机名
	 * @param port
	 *            服务器端口
	 * @return 远程服务
	 * @throws Exception
	 */
	@SuppressWarnings("unchecked")
	public static <T> T refer(final Class<T> interfaceClass, final String host, final int port) throws Exception {
		if (interfaceClass == null)
			throw new IllegalArgumentException("Interface class == null");
		if (!interfaceClass.isInterface())
			throw new IllegalArgumentException("The " + interfaceClass.getName() + " must be interface class!");
		if (host == null || host.length() == 0)
			throw new IllegalArgumentException("Host == null!");
		if (port <= 0 || port > 65535)
			throw new IllegalArgumentException("Invalid port " + port);
		System.out.println("Get remote service " + interfaceClass.getName() + " from server " + host + ":" + port);
		// JDK的动态实现代码
		return (T) Proxy.newProxyInstance(interfaceClass.getClassLoader(), new Class<?>[] { interfaceClass },
				new InvocationHandler() {
					public Object invoke(Object proxy, Method method, Object[] arguments) throws Throwable {
						Socket socket = new Socket(host, port);
						try {
							ObjectOutputStream output = new ObjectOutputStream(socket.getOutputStream());
							try {
								output.writeUTF(method.getName());
								output.writeObject(method.getParameterTypes());
								output.writeObject(arguments);
								ObjectInputStream input = new ObjectInputStream(socket.getInputStream());
								try {
									Object result = input.readObject();
									if (result instanceof Throwable) {
										throw (Throwable) result;
									}
									return result;
								} finally {
									input.close();
								}
							} finally {
								output.close();
							}
						} finally {
							socket.close();
						}
					}
				});
	}
}
